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Re: [Qemu-devel] [PATCH v5 00/22] instrument: Add basic event instrument
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v5 00/22] instrument: Add basic event instrumentation |
Date: |
Thu, 14 Sep 2017 15:54:28 +0100 |
On 12 September 2017 at 22:01, Lluís Vilanova <address@hidden> wrote:
> This series adds an API to add instrumentation events.
>
> It also provides additional APIs for:
> * Controlling tracing events.
> * Peek/poke guest memory.
> Future APIs (for later series):
> * Peek/poke guest registers.
> * Add breakpoints to trigger instrumentation functions.
> * Trigger instrumentation functions from guest code (former hypertrace).
> * Add events for guest code translation/execution (once the respective tracing
> events are accepted upstream).
> * Add events for exceptions/syscalls.
> * Add events for TB invalidation (necessary for libraries to deallocate any
> data
> they might have allocated for the TBs they instrumented).
>
> The instrumentation code is dynamically loaded as a library into QEMU either
> when it starts or later using its remote control interfaces. The loaded code
> only has access to function explicitly exported through the QI_VPUBLIC macro.
>
> This series is branch 'devel-instrument' in
> https://code.gso.ac.upc.edu/git/qemu-dbi.
To parallel the comment I sent on Emilio's series: I think the
first thing we should do here is work out the API we want to
present to the instrumentation plugin, because that's permanent
and we want to get it right. Then we can figure out the
implementation details later.
Particular notes:
* putting things in the instrumentation plugin API that basically
parallel some existing trace points is something I'm wary of,
because a lot of our existing tracing is "output something at
a point and in a way that's convenient for our internal
implementation", rather than "what is the right clean interface
to provide this sort of information". I'd rather we started
with a blank piece of paper and designed an API, and then
implemented it.
* I definitely don't think we should expose to the instrumentation
the distinction between translate time and execute time
thanks
-- PMM
- [Qemu-devel] [PATCH v5 17/22] trace: Introduce a proper structure to describe memory accesses, (continued)
- [Qemu-devel] [PATCH v5 17/22] trace: Introduce a proper structure to describe memory accesses, Lluís Vilanova, 2017/09/12
- [Qemu-devel] [PATCH v5 18/22] instrument: Add event 'guest_mem_before_trans', Lluís Vilanova, 2017/09/12
- [Qemu-devel] [PATCH v5 19/22] instrument: Add event 'guest_mem_before_exec', Lluís Vilanova, 2017/09/12
- [Qemu-devel] [PATCH v5 20/22] instrument: Add event 'guest_user_syscall', Lluís Vilanova, 2017/09/12
- [Qemu-devel] [PATCH v5 21/22] instrument: Add event 'guest_user_syscall_ret', Lluís Vilanova, 2017/09/12
- [Qemu-devel] [PATCH v5 22/22] instrument: Add API to manipulate guest memory, Lluís Vilanova, 2017/09/12
- Re: [Qemu-devel] [PATCH v5 00/22] instrument: Add basic event instrumentation, no-reply, 2017/09/12
- Re: [Qemu-devel] [PATCH v5 00/22] instrument: Add basic event instrumentation, no-reply, 2017/09/12
- Re: [Qemu-devel] [PATCH v5 00/22] instrument: Add basic event instrumentation,
Peter Maydell <=